Single-phase pole-mounted transformers: The cornerstone of modern power distribution excellence.
01 General
1.1 Project Description
The 25 KVA pole mounted transformer was delivered to Guyana in 2024. The rated power of the pole mounted transformer is 25 KVA with ONAN cooling, the primary voltage is 13.8 kV with ±2*2.5% tapping range (NLTC), the secondary voltage is 0.12/0.24 kV, they formed a vector group of li0. Single-phase pole transformers are widely used in power distribution systems to reduce voltage to meet the electricity needs of homes and small commercial users. It is usually installed on the pole of the power transmission and distribution network, so it is named “pole transformer”.
This type of transformer converts high voltage current to a lower operating voltage through a single-phase power supply, ensuring minimal power loss during transmission. It consists of a primary winding, a secondary winding and an iron core. Rod transformers are compact and easy to install, making them ideal for power distribution in urban and rural areas.
In addition, single-phase pole transformers are relatively simple in terms of operation and maintenance, and can operate stably under various environmental conditions. Its protective design is often designed to withstand severe weather and external influences, ensuring the reliability of the power supply. In short, such transformers are an indispensable and important part of modern power networks.
1.2 Technical Specification
25 KVA transformer specifications type and data sheet
| Delivered to | Guyana |
| Year | 2024 |
| Type | Pole mounted transformer |
| Standard | IEEE C57.12.00 |
| Rated Power | 25KVA |
| Frequency | 60HZ |
| Phase | 1 |
| Cooling Type | ONAN |
| Primary Voltage | 13.8KV |
| Secondary Voltage | 0.12/0.24 KV |
| Winding Material | Aluminum |
| Angular displacement | li0 |
| Impedance | 2.2% |
| Tap Changer | NLTC |
| Tapping Range | ±2*2.5% |
| No Load Loss | 0.098KW |
| On Load Loss | 0.289KW |
| Accessories | Standard Configuration |
1.3 Drawings
25 KVA pole mounted transformer diagram drawing and size.
02 Manufacturing
2.1 Core
| The coil core is wound by multiple layers of banded silicon steel sheets to form a circular or square closed magnetic circuit. The winding method can not only improve the magnetism by reducing the grain size of the material, but also increase the filling rate of the iron core. In order to reduce eddy current losses, the silicon steel sheets are arranged closely at high pressure during winding, and some shapes are “shear” or “pressure”, depending on the design requirements of the transformer. Each layer of silicon steel sheet in the core is usually coated with an insulating coating to prevent eddy currents between the layers. The closed magnetic circuit composed of rolled iron core enhances the magnetic flux density and makes it more efficient in electromagnetic induction. By optimizing material selection and structural design, coil core can effectively reduce the energy loss (such as hysteresis loss and eddy current loss) generated during transformer operation. The design of the iron core involves the turn ratio of the primary and secondary windings to ensure that the voltage conversion ratio of the transformer meets the requirements. Because the structure is relatively closed, the noise generated by the coil core during operation is less. |  |
2.2 Winding
 | Low pressure foil winding Automatic foil winding machine, TIG argon arc welding, guideway rolling shear, PLC control system, photoelectric induction automatic correction system, high speed and high precision winding. Frequency conversion stepless speed regulation, photoelectric induction automatic correction. Once the winding is completed, the outer surface of the inner and outer leads of the coil is bandaged. The end of the foil winding is neat and its end leakage is less, which makes the sudden short-circuit force small and the anti-short-circuit ability enhanced. The voltage between layers of foil coil is equal to the voltage between turns, and the voltage between layers is lower. For wire-wound products, because the voltage is not high, it is easy to design and manufacture. |
2.3 Tank
| The tank is made of high-quality stainless steel to ensure that the tank has good mechanical strength and corrosion resistance. According to the design drawing, the shears are used to cut the steel plate to the desired size and shape. By stamping or bending process, the cut steel plate is made into various parts of the tank (such as bottom plate, side plate, top plate, etc.). The components are assembled into the tank using gas shielded welding (MIG welding) or arc welding. When welding, ensure the tightness and strength of the weld. The weld is polished after welding to eliminate burrs and unevenness. |  |
2.4 Final Assembly
03 Testing
| No. | Test Item | Unit | Acceptance Values | Measured Values | Conclusion |
| 1 | Resistance Measurements | / | / | / | Pass |
| 2 | Ratio Tests | / | The deviation of voltage ratio on the principal tapping: ≤0.5% Connection symbol: Ii0 | -0.03 | Pass |
| 3 | Polarity tests | / | Subtractive | Subtractive | Pass |
| 4 | No-load losses and excitation current | % kW | I0 : provide measured value P0: provide measured value the tolerance for no load loss is +10% | 1.44 0.084 | Pass |
| 5 | Load losses, impedance voltage,total losses and efficiency | / kW kW | t: 85℃ Z%: measured value Pk: measured value Pt: measured value the tolerance for impedance is ±10% the tolerance for total load loss is +6% | 2.41 0.296 0.380 98.80 | Pass |
| 6 | Applied Voltage Test | / | HV: 34KV 60s LV: 10kV 60s | No collapse of the test voltage occurs | Pass |
| 7 | Induced Voltage Withstand Test | / | Applied voltage (KV): 2 Ur Duration(s): 48 Frequency (HZ): 150 | No collapse of the test voltage occurs | Pass |
| 8 | Insulation Resistance Measurement | GΩ | HV-LV to Ground LV-HV to Ground HV&LV to Ground | 79.6 78.3 78.1 | / |
| 9 | Leakage Test | / | Applied pressure: 20kPA Duration: 12h | No leakage and No Damage | Pass |
| 10 | Oil Dielectric Test | kV | ≥45 | 52.18 | Pass |
04 Packing and Shipping
05 Site And Summary
Thank you for your interest and support in our single-phase pole-mounted transformer! With its exceptional performance, stable operation, and energy-efficient features, this product meets power demands across various applications, providing reliable support for power systems. We will continue to innovate and are committed to delivering high-quality products and services. We look forward to working with you to create a brighter future for the power industry together!
